Field testing in the electric utility industry presents challenges in that extremely varying conditions such as temperature and other environmental conditions can have adverse effects on testing equipment. For example, the extreme range of temperatures that one may encounter in climates varying from sub-freezing temperatures in near polar areas to the sweltering temperatures found in other geographic regions have typically demanded that conventional measuring equipment include expensive components to handle wide ranging environmental and operational conditions. Such conventional configurations may also typically be difficult to transport and be quite heavy and bulky.
Several other of the many challenges in field testing, particularly in the area of current measurement, are due to the sheer differences in magnitude of current signals encountered. For example, a high current load in a factory is vastly different than a high current load in a residential home. Therefore, a device is needed that is capable of testing large ranges of current. However, care has to be taken in the design of measurement circuitry on the secondary side of a measurement device including a current transformer, due to the additional burden on the current transformer that is produced with any load-increasing components. Also, some conventional current measurement devices employ different circuits that must be selected by switching according to the level of current involved. Not only do these conventional circuits introduce too much burden on the secondary side of the current transformer, but data-loss incurred during the switching between the circuits results in losses of revenue from the companies supplying the power to the customers for whom the measurements are being taken. Thus, a device to measure current with a low secondary burden is desired, and one that minimizes losses when switching between different current ranges.
Thus, a sturdy and readily portable device to overcome these challenges, as well as other functions such as effective analog to digital conversion and other conditioning of the signals that are helpful in the analysis of the measured signals, is desired.